Two keys appear to be permanently linked and, no matter how you look at it, ...

Two keys appear to be permanently linked and, no matter how you look at it, there is seemingly no solution to unlocking them. However, as a highly popular puzzle since its creation during the 19th century puzzle craze, the keys are in fact separable.

This classic metal take-apart puzzle features fine decorative horseshoes as well as solid construction. The objective is to remove the ring from the horseshoes without forcing or bending any of the elements. Though this puzzle is well-known, the solution is trickier than you might think!

The Tangled Nails are actually two regular nails bent and entangled togeth...

The Tangled Nails are actually two regular nails bent and entangled together. The object is to just find a way to separate them. As an added challenge, try to entangle them back again, which can be even harder. This simple and yet fascinating design uses two identical pieces and the solution is based on a beautiful symmetry.